Walk into a used book store to get a book that you hope is still on the shelves from the last time you were there and got really excited to see it and almost bought it before looking at the price and thinking "$12 for a book from a used bookstore? I can get this on paperback for $10 at the Book Warehouse" and then leaving with a mixture of victory and shame.
Notice, as you walk straight to the theatre section (where you know the book lives) that some tall man-shaped person seemed to notice you as you walked by.
Think that you must be looking particularly stunning today as you just got checked out in a used book store.
From the theatre section try to check out the tall man-shaped person who seemed to notice you, but their back is turned so you can't tell anything about their appearance except that they remain to be tall and man-shaped.
Remind yourself that it's not sexist to call someone man-shaped because there are general differences in body shape and size between the sexes, and this is definitely of the man-specific variety.
Turn back to the shelf to look for the pretentious theatre theory book you want to read for fun and notice movement at your side that is probably the man-shaped person approaching you. Think that you must really be looking stunning because this man-shaped person seems to now be approaching you.
Feel really good about yourself and the fact that you have a new, open attitude towards dating and talking to people you don't know and everything. Remember how much more confident and self-assured you have been lately and think of how well the pending conversation is likely to go.
Hear the man-shaped person say something probably along the lines of, "hey."
Turn to look at them.
See that they are a dude you went to high school with.
Have nothing to talk about because you already pretty much know what each other is up to because even though you haven't talked in years, you're both on facebook and facebook has removed the possibility for catching up with old acquaintances in person, so instead you end up saying things like "I saw on facebook that you...." and the other person can't say much more than "yep, that's what I'm doing - oh facebook!" and then you both laugh awkwardly and linger for a few moments before he finds an excuse to leave the conversation.
Realize that instead of getting checked out and chatted up by a potentially attractive used-book store patron, you have been a part of what might as well have been a scene in one of those awkward romantic comedies where the main character undergoes a drastic transformation and this is the establishing scene to show how much of a social pariah she was in the beginning, and highlight how significant her journey will be in the end.
Feel that dirty feeling that awkward run-ins bring, wander around used book store for 10 minutes to try to shake it off before leaving without buying the book you came in for.